Working i386 paging and liballoc

kernel/platform/i386_pc/boot/.gitignore

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+*.o

kernel/platform/i386_pc/boot/_start.S

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+/*
+Copyright 2025 Kamil Kowalczyk
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the following
+conditions are met:
+
+1. Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#define F_MEMALIGN  (1<<0)
+#define F_MEMINFO   (1<<1)
+
+#define FLAGS     (F_MEMALIGN | F_MEMINFO)
+#define MAGIC     (0x1BADB002)
+#define CHECKSUM  (-(MAGIC + FLAGS))
+
+#define VIRT_BASE   0xC0000000
+
+.section .multiboot, "aw"
+  .align 4
+  .long MAGIC
+  .long FLAGS
+  .long CHECKSUM
+
+.section .bss
+  .align 16
+  __stack_bottom:
+    .skip 16384
+  __stack_top:
+
+.section .boot, "ax"
+  .global _start
+  _start:
+    movl $(__init_pd - VIRT_BASE), %ecx
+    movl %ecx, %cr3
+
+    movl %cr4, %ecx
+    orl $0x10, %ecx
+    movl %ecx, %cr4
+
+    movl %cr0, %ecx
+    orl $0x80000000, %ecx
+    movl %ecx, %cr0
+
+    movl $__kernel_higherhalf, %ecx
+    jmp *%ecx
+
+.section .text, "ax"
+  __kernel_higherhalf:
+    mov $__stack_top, %esp
+    push %ebx
+    xorl %ebp, %ebp
+    call bootmain
+  1:
+    hlt
+    jmp 1b
+
+.section .data
+  .align 4096
+  .global __init_pd
+  __init_pd:
+    .long 0b10000011
+    .rept 768-1
+      .long 0
+    .endr
+    .long (0 << 22) | 0b10000011
+    .long (1 << 22) | 0b10000011
+    .long (2 << 22) | 0b10000011
+    .long (3 << 22) | 0b10000011
+    .rept 256-4
+      .long 0
+    .endr
+

kernel/platform/i386_pc/boot/bootmain.c

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+/*
+Copyright 2025 Kamil Kowalczyk
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the following
+conditions are met:
+
+1. Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <libk/types.h>
+#include <libk/util.h>
+#include <libk/string.h>
+#include <sys/cpu.h>
+#include <sys/multiboot.h>
+#include <sys/serialdbg.h>
+#include <sys/mm.h>
+#include <mm/pmm.h>
+#include <mm/bba.h>
+#include <mm/liballoc.h>
+#include <config.h>
+
+extern byte_t __kernel_end;
+
+static void dump_multiboot_header(void) {
+  struct multiboot *mb = multiboot_get();
+
+  dbgf("multiboot=%p\n", mb);
+  dbgf("multiboot sanity dump:\n");
+  dbgf("flags=%08x, mem_low=%08x, mem_up=%08x\n",
+      mb->flags, mb->mem_low, mb->mem_up);
+}
+
+static void pmm_init1(void) {
+  struct multiboot *mb = multiboot_get();
+
+  dbgf("__kernel_end=%p, %p\n", &__kernel_end, (uptr_t)&__kernel_end - VIRT_BASE);
+
+  usize_t usable_ram_bytes = mb->mem_up * 1024;
+  dbgf("usable ram = %zu\n", usable_ram_bytes);
+
+  uptr_t ram_start = ALIGN_UP((uptr_t)&__kernel_end - VIRT_BASE, 0x1000);
+  uptr_t ram_end = ALIGN_DOWN(0x100000 + usable_ram_bytes, 0x1000);
+
+  usize_t block_size = CFG_I386_PC_PMM_BLOCK_SIZE;
+  usize_t block_count = (ram_end - ram_start) / block_size;
+
+  usize_t pmm_bm_bytes = ALIGN_UP((block_count + 7) / 8, block_size);
+
+  uptr_t pmm_bm_baseptr = ram_start;
+  uptr_t pmm_baseptr = ram_start + pmm_bm_bytes;
+
+  usize_t remaining_blocks = (ram_end - pmm_baseptr) / block_size;
+
+  dbgf("ram_start=%p, pmm_bm_baseptr=%p, pmm_baseptr=%p\n",
+      ram_start, pmm_bm_baseptr, pmm_baseptr);
+  pmm_init(pmm_baseptr, pmm_bm_baseptr, remaining_blocks, block_size);
+}
+
+void bootmain(void *mbootptr) {
+  multiboot_set((struct multiboot *)VIRT(mbootptr));
+
+  cpu_init();
+
+#if CFG_I386_PC_DEBUG == CFG_I386_PC_DEBUG_SERIAL
+  serialdbg_init();
+  dbgf("dbgf() test...\n");
+#endif
+
+  dump_multiboot_header();
+  pmm_init1();
+  bba_init();
+  mm_init();
+
+  char *string = malloc(12);
+  memset(string, 0, 12);
+  strncpy(string, "Hello world", 12);
+  dbgf("string = %s\n", string);
+  free(string);
+
+  for (;;);
+}

kernel/platform/i386_pc/boot/make.src

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+dir_boot := $(patsubst %/,%,$(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
+
+c_files += $(dir_boot)/bootmain.c
+
+S_files += $(dir_boot)/_start.S
+
+o_files += $(dir_boot)/bootmain.o \
+           $(dir_boot)/_start.o